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#1
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Army interferes with garage doors.
mm wrote:
Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) If you are inclined to email me for some reason, remove NOPSAM :-) read he http://www.ddc.dla.mil/news/2005_02_...arage_Door.pdf |
#2
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Army interferes with garage doors.
"mm" wrote in message ... Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) Front end swamping ? Garage door openers are coded so that your remote doesn't open every door in the street ?? Arfa |
#3
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Army interferes with garage doors.
On Sat, 08 Mar 2008 12:40:08 -0500, mm
wrote: Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? No, they don't. Shared and the primary user (military) has priority, all non-primary users much accept any interference generated by the primary user. 2) How could the use of a frequency mess up the garage door openers? Well, if two signals could occupy the same frequency, we'd only need televisions with one channel, right? Even if the govt. signal was stronger, why wouldn't the opener still work? OK, so your car's FM radio picks up a given station. It picks up the strongest station, in fact if that strongest station were to suddnly stop transmitting (say a power or equipment failure) you'd then probably pick up the next strongest station on the same frequency... Strongest wins, in this and in fighting. If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) Huh? So the military signal overpowers the remote... How's it going to work? If you are inclined to email me for some reason, remove NOPSAM :-) |
#4
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Army interferes with garage doors.
mm wrote:
If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) For the same reason that all garage doors don't open when you push the remote for one. -- If only there was a Republican running for President of the United States. |
#5
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Army interferes with garage doors.
On 03/08/08 12:40 pm mm wrote:
Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) Garage door openers (and a bunch of other household electronic devices (e.g., cordless phones, computers, wireless networking systems, wireless remote temperature/humidity sensors) are unlicensed devices governed by Part 15 of the FCC regs. They must not interfere with licensed services but must put up with any interference from licensed services. So if your garage door opener interferes with your ham-radio neighbor's communications, it's your responsibility to fix the problem (e.g., by replacing or refraining from using the offending device). Similarly, as long as your ham-radio neighbor is operating within the terms of his/her license and you keep hearing him/her in your cordless phone, that again is your problem -- although he/she ought to be willing to assist you in finding a solution to the problem (but is under no obligation to actually fix the problem or pay for somebody else to fix the problem). Perce |
#6
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Army interferes with garage doors.
1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? As someone else stated the front end of the garage door openers receiver is being swamped by a strong signal. This signal need not be the same frequency. It only has to be very strong and dilute the remote so that it can not be picked up. |
#7
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Army interferes with garage doors.
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#8
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Army interferes with garage doors.
Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) If you are inclined to email me for some reason, remove NOPSAM :-) |
#9
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Army interferes with garage doors.
mm wrote:
Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) If you are inclined to email me for some reason, remove NOPSAM :-) I have used these openers for datatransmission, and the type I used had 8 tri_state codeswitches. If the code does not fit, nothing happens, when some outside transmitter intervenes. The codestring contained about 42 bytes in total, and it is difficult to trigger that with some random signal. In case of interference, you just have to get closer to your receiver, for it to work. |
#10
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Army interferes with garage doors.
"Percival P. Cassidy" wrote in message ... On 03/08/08 12:40 pm mm wrote: Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) Garage door openers (and a bunch of other household electronic devices (e.g., cordless phones, computers, wireless networking systems, wireless remote temperature/humidity sensors) are unlicensed devices governed by Part 15 of the FCC regs. They must not interfere with licensed services but must put up with any interference from licensed services. So if your garage door opener interferes with your ham-radio neighbor's communications, it's your responsibility to fix the problem (e.g., by replacing or refraining from using the offending device). Similarly, as long as your ham-radio neighbor is operating within the terms of his/her license and you keep hearing him/her in your cordless phone, that again is your problem -- although he/she ought to be willing to assist you in finding a solution to the problem (but is under no obligation to actually fix the problem or pay for somebody else to fix the problem). Perce This is the same sort of problem that some Chrysler cars had in the 90s. If you drove by a powerful radar installation, and the beam hit your car, it would stall due to interference with the electronic ignition/computer components in the car. The car manufacturer had to come up with a modification to harden the engine's controls to the radar signal. |
#11
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Army interferes with garage doors.
sounds like some bs to me.
s "mm" wrote in message ... Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) If you are inclined to email me for some reason, remove NOPSAM :-) |
#12
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Army interferes with garage doors.
mm wrote:
Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) If you are inclined to email me for some reason, remove NOPSAM :-) Must be a slow news day in Maryland- this has been going on for years, at multiple bases, and even at some civil airports. Like others in the thread have said, homeowners are legally SOL- low-power non-licensed consumer devices are not protected. Megawatts versus milliwatts, the big-ass transmitter will simply overpower the tiny one. Sometimes repositioning or changing the length of the antenna pickup wire attached to the opener can help. Sound like the local garage door companies have their shears out. Did the article say if the base was working with the locals, to maybe fine-tune reality a tad, and move their transmitter to a freq that would cause less problems, or reorient the transmitting antenna? They aren't obligated to, but base commanders hate having the locals all ****y with them. They have done that at some bases, to include providing the local media with how-to guides about moving the antenna wire in the garage and such. aem sends... |
#13
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Army interferes with garage doors.
"S. Barker" wrote in message ... sounds like some bs to me. s Why ?? Arfa |
#14
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Army interferes with garage doors.
In article ,
mm wrote: Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? Not really. The garage door openers are "Part 15" devices - they don't have a reserved frequency allocation. Instead, they (and other low-power devices) are allowed to use a wide range of frequencies that are primarily allocated for other radio services. 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) A lot of unlicensed (Part 15) devices such as garage door openers and car-alarm keyfobs use frequencies around 433.920 MHz. The primary usage allocation for this frequency band is government echolocation (radar). Ham radio operators have a secondary allocation (i.e. they can use it as long as they don't interfere with government radar). Unlicensed users are tertiary, and have *no* legal protection against interference from licensed, or other unlicensed users. The transmitters for these Part 15 devices use very low power, by design and law. The receivers for them are, well, let's say "inexpensively made" - they tend to be reasonably sensitive (so that they can pick up the weak signals from the transmitters) but are not at all selective. Strong signals from other transmitters, on the same or nearby frequency bands, can overload (saturate) the RF front end circuitry in these receivers - a phenomenon known as desensitization or "desense". When this happens, a strong transmission can completely block the weaker one, even if the actual frequencies of the two transmissions don't overlap at all. It's sort of like trying to hear a low-pitched voice speaking quietly in the next room, when somebody is blasting your eardrums with a piccolo :-) -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#15
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Army interferes with garage doors.
"aemeijers" wrote in message ... snip Did the article say if the base was working with the locals, to maybe fine-tune reality a tad, and move their transmitter to a freq that would cause less problems, or reorient the transmitting antenna? They aren't obligated to, but base commanders hate having the locals all ****y with them. They have done that at some bases, to include providing the local media with how-to guides about moving the antenna wire in the garage and such. aem sends... the base is under no obligation to do anything. some base commanders have chosen to create more trouble for themselves by attempting to accomodate the "locals". they then discover the cost associated with any "mitigation" strategy to be cost prohibitive. there is no one single "transmitter". there are several - these are Motorola digital APCO P25 trunking systems. a "control channel" is continously transmitting 24/7. the other transmitters will key up to carry voice traffic as needed (as assigned by the central controller, the "brains" of the system). it is NOT a simple process to modify the frequency bandplan due to the domino effect on the rest of the system. trunking central controllers would need to be reprogrammed, databases changed, subscribers (ie. the hundreds of portable walkie talkies and mobiles in the field) would need to be bought in and reprogrammed, and RF transmit combiners would need to be retuned. These are NOT simple tasks ! "reorienting" an antenna is not going to work either. the coverage on these systems is OMNI directional (ie. we strive to provide a perfect circle, if possible). the typical goal is 95% coverage for a portable. in practice, we can usually achieve numbers greater than that. now, if a spineless base commander wants to pay the several hundred thousand dollars to do a new engineering study and then the actual man hours involved in implementing a frequency change (that they are under ZERO obligation to do), then i'm sure the vendor (Motorola) would be more than happy to accomodate them - just show them the money ! however, it's unlikely any new frequency within the assigned govt. spectrum will solve the problem. you're always going to have some part 15 device affected. the answer is better engineering on the consumer side (ie. move the devices to another frequency band, and tighten up the front end selectivity on the receiver). |
#16
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Army interferes with garage doors.
noespaem wrote:
"aemeijers" wrote in message ... snip Did the article say if the base was working with the locals, to maybe fine-tune reality a tad, and move their transmitter to a freq that would cause less problems, or reorient the transmitting antenna? They aren't obligated to, but base commanders hate having the locals all ****y with them. They have done that at some bases, to include providing the local media with how-to guides about moving the antenna wire in the garage and such. aem sends... the base is under no obligation to do anything. some base commanders have chosen to create more trouble for themselves by attempting to accomodate the "locals". they then discover the cost associated with any "mitigation" strategy to be cost prohibitive. there is no one single "transmitter". there are several - these are Motorola digital APCO P25 trunking systems. a "control channel" is continously transmitting 24/7. the other transmitters will key up to carry voice traffic as needed (as assigned by the central controller, the "brains" of the system). it is NOT a simple process to modify the frequency bandplan due to the domino effect on the rest of the system. trunking central controllers would need to be reprogrammed, databases changed, subscribers (ie. the hundreds of portable walkie talkies and mobiles in the field) would need to be bought in and reprogrammed, and RF transmit combiners would need to be retuned. These are NOT simple tasks ! "reorienting" an antenna is not going to work either. the coverage on these systems is OMNI directional (ie. we strive to provide a perfect circle, if possible). the typical goal is 95% coverage for a portable. in practice, we can usually achieve numbers greater than that. now, if a spineless base commander wants to pay the several hundred thousand dollars to do a new engineering study and then the actual man hours involved in implementing a frequency change (that they are under ZERO obligation to do), then i'm sure the vendor (Motorola) would be more than happy to accomodate them - just show them the money ! however, it's unlikely any new frequency within the assigned govt. spectrum will solve the problem. you're always going to have some part 15 device affected. the answer is better engineering on the consumer side (ie. move the devices to another frequency band, and tighten up the front end selectivity on the receiver). Don't know about the current case, but the ones previously written up were NOT LMR systems, trunked APCO p25 or otherwise- they were radar r&d sites. One of my duties at work is buying LMR systems, so I do understand how those work. (or in the case of the local public safety LMR, NOT work.) I've never heard of a trunking control channel causing problems for garage door openers- the repeaters just aren't that powerful. I suppose it is possible, but reorienting the antenna for the part 15 device usually would fix that. No, a base commander is not gonna break his budget or compromise mission capability to keep the locals happy. But since 'having a good working relationship with local civil authorities' is one of the things he gets rated on, he isn't gonna tell them to eff off, either. Having a senior tech and a PR flack give a few tours, and provide info to local media, can go a long way. aem sends... |
#17
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Army interferes with garage doors.
"Sjouke Burry" wrote in message ... mm wrote: Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) If you are inclined to email me for some reason, remove NOPSAM :-) I have used these openers for datatransmission, and the type I used had 8 tri_state codeswitches. If the code does not fit, nothing happens, when some outside transmitter intervenes. The codestring contained about 42 bytes in total, and it is difficult to trigger that with some random signal. In case of interference, you just have to get closer to your receiver, for it to work. Or get a signal amplifier, although I'm sure that is not legal. Mike |
#18
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Army interferes with garage doors.
Michael Kennedy wrote:
"Sjouke Burry" wrote in message ... In case of interference, you just have to get closer to your receiver, for it to work. Or get a signal amplifier, although I'm sure that is not legal. That's it, a garage door opener transmitter with a 500-watt linear amplifier. -- If only there was a Republican running for President of the United States. |
#19
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Army interferes with garage doors.
"aemeijers" wrote in message news:bcWAj.732298$kj1.552302@bgtnsc04- snip Don't know about the current case, but the ones previously written up were NOT LMR systems, trunked APCO p25 or otherwise- they were radar r&d sites. the new system at Eglin AFB ran afoul of some locals in the developments nearby (who discovered their garage door openers were being hit with the equivalent of a jammer - the emitter being the control channel of the new trunking system). there have been other reports of similar spectrum issues at other installations. now in a different reverse case, the military is claiming amateur radio repeaters are interfering with some PAVE PAWS radar sites. which the ARRL is cooperating with them to address the issues. One of my duties at work is buying LMR systems, so I do understand how those work. (or in the case of the local public safety LMR, NOT work.) is "MA/COM" in that scenario ? I've never heard of a trunking control channel causing problems for garage door openers- the repeaters just aren't that powerful. typical output on a licensed transmitter is approximately 55 watts out of the transmit combiner to, say a 100' high, 7 db gain antenna. so anyone can do the math here. a nominal receiver sensitivity number for receiver 5% BER (on the subscriber side) is probably about -120 dbm of signal. the "average" part 15 consumer device is hard of hearing to begin with (compared to a $4000 high end Motorola unit). so it has some attenuation hearing it's intended signal (the remote) to begin with. flooding the area with the control channel signal only adds to the noise mask the garage door receiver would need to struggle against. also keep in mind, these systems operate in the spectrum slots assigned to US federal govt users. so, it's not going to be the 800 mhz, or 450-512 band slices. the remote manufacturers rolled the dice (on operating on frequencies that could be reclaimed by the govt at anytime), and they lost. unfortunately the consumer is caught in the middle. of course, the manufacturers specifically have wording in their manuals that address the possibility of interference and disclaim all liability for same. I suppose it is possible, but reorienting the antenna for the part 15 device usually would fix that. see above, maybe, maybe not - probably not. No, a base commander is not gonna break his budget or compromise mission capability to keep the locals happy. But since 'having a good working relationship with local civil authorities' is one of the things he gets rated on, he isn't gonna tell them to eff off, either. Having a senior tech and a PR flack give a few tours, and provide info to local media, can go a long way. agreed, most CO's are politically savvy (unfortunately so in some cases, but we won't go there). aem sends... |
#20
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Army interferes with garage doors.
On Mar 8, 1:40*pm, mm wrote:
Today on the news I heard that a big bunch of electronic garage door openers weren't working in Churchville Maryland because the govt. at the Aberdeen Proving Grounds was doing something with a satellite or something. *Tomorrow their going to do the same thing around Aberdeen. People are paying techs to change the freqs, but some may have paid for other repairs by mistake, one would assume. * Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? *If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) If you are inclined to email me for some reason, remove NOPSAM *:-) some may have paid for other repairs by mistake, one would assume. You know what happens when one assumes... |
#21
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Army interferes with garage doors.
noespaem wrote:
"aemeijers" wrote in message news:bcWAj.732298$kj1.552302@bgtnsc04- snip (very interesting info snipped) No, the local PD/Fire system is a statewide 800 band Motorola p25 trunked(which a lot of Federal users are jumping onto as well), with not enough towers, leading to multiple dead spots, especially in steel-frame buildings. Said dead spots aggravated by the insistence at running even routine comms encrypted. Thank heavens I don't have to deal with that mess. (My office has vanilla vhf with a very tall repeater- stone age, but works great.)I mostly spec and buy vanilla vhf, or trunked 380-412. Don't think I ever bought any MA/COM, though. Wherever possible, I am cutting our sites over from standalone systems to be tenants on host trunk system, so I buy what they can support locally. (lots of XTS5000, lately) aem sends... |
#22
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Army interferes with garage doors.
"clifto" wrote in message ... Michael Kennedy wrote: "Sjouke Burry" wrote in message ... In case of interference, you just have to get closer to your receiver, for it to work. Or get a signal amplifier, although I'm sure that is not legal. That's it, a garage door opener transmitter with a 500-watt linear amplifier. My thoughts exactly. I could open my garage door from anywhere in the state. |
#23
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Army interferes with garage doors.
In article ,
Michael Kennedy wrote: Or get a signal amplifier, although I'm sure that is not legal. That's it, a garage door opener transmitter with a 500-watt linear amplifier. My thoughts exactly. I could open my garage door from anywhere in the state. I can't help envisioning the situation. Driver presses the "open" button, the car's engine labors and stalls under the load of powering the amplifier, and the garage door snaps open so fast that it rams right through the back of the garage and skims out into the yard like a Frisbee (tm). -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#24
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Army interferes with garage doors.
Michael Kennedy wrote:
"clifto" wrote in message ... Michael Kennedy wrote: "Sjouke Burry" wrote in message ... In case of interference, you just have to get closer to your receiver, for it to work. Or get a signal amplifier, although I'm sure that is not legal. That's it, a garage door opener transmitter with a 500-watt linear amplifier. My thoughts exactly. I could open my garage door from anywhere in the state. Have you ever looked at the circuitry in a garage door opener receiver? No pre-amp, not much more than a tuned circuit feeding the mixer. Some older units were TRF broadband, and used simple tone modulation. -- My sig file can beat up your sig file! |
#25
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Army interferes with garage doors.
"Michael A. Terrell" wrote in message ... Michael Kennedy wrote: "clifto" wrote in message ... Michael Kennedy wrote: "Sjouke Burry" wrote in message ... In case of interference, you just have to get closer to your receiver, for it to work. Or get a signal amplifier, although I'm sure that is not legal. That's it, a garage door opener transmitter with a 500-watt linear amplifier. My thoughts exactly. I could open my garage door from anywhere in the state. Have you ever looked at the circuitry in a garage door opener receiver? No pre-amp, not much more than a tuned circuit feeding the mixer. Some older units were TRF broadband, and used simple tone modulation. -- My sig file can beat up your sig file! No, I've never taken one apaprt. I didn't realize that they were so simple, but then again I don't have a garage door opener, or a garage door for that matter. Mike |
#26
Posted to sci.electronics.repair,alt.home.repair
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Army interferes with garage doors.
Michael Kennedy wrote:
No, I've never taken one apaprt. I didn't realize that they were so simple, but then again I don't have a garage door opener, or a garage door for that matter. Most of them are so poorly designed you wonder how they work, at all. I had a friend who owned a garage door business, and ended up repairing the things for a few years. I even repaired one of the '50s transmitters that was mounted under the hood of a car. What a piece of junk! -- My sig file can beat up your sig file! |
#27
Posted to sci.electronics.repair,alt.home.repair
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Army interferes with garage doors.
On Sat, 08 Mar 2008 23:10:53 GMT, aemeijers wrote:
Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) Must be a slow news day in Maryland- Every day is a slow news day in Maryland. I miss NYC where the local news was often as interesting as the national news. Like when I rode my bicycle by the US mission to the UN and the door was bombed an hour later, iirc. Maybe it was a day later, but still. this has been going on for years, Thanks to everyone. If you are inclined to email me for some reason, remove NOPSAM :-) |
#28
Posted to sci.electronics.repair,alt.home.repair
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Army interferes with garage doors.
"mm" wrote in message ... On Sat, 08 Mar 2008 23:10:53 GMT, aemeijers wrote: Someone in charge admits he didn't get the word out well enough. 1) Don't they assign frequency ranges to things so that this sort of thing doesn't happen? 2) How could the use of a frequency mess up the garage door openers? Even if the govt. signal was stronger, why wouldn't the opener still work? If the govt. signal was picked up by the opener, how come the doors didn't open or shut. (Apparently they didn't since they would surely have mentioned that.) Must be a slow news day in Maryland- Every day is a slow news day in Maryland. I miss NYC where the local news was often as interesting as the national news. Like when I rode my bicycle by the US mission to the UN and the door was bombed an hour later, iirc. Maybe it was a day later, but still. this has been going on for years, Thanks to everyone. If you are inclined to email me for some reason, remove NOPSAM :-) Try the news in Orlando.. Nothing compared to NYC, but there is a shooting every night! Crime has been on the rise here for the last 4 years or so. I'd rather have no news and low crime. Mike |
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